After exposing a silver halide photographic photosensitive material, the colored image is formed by a reaction between the primary aromatic amine developing agent which has been oxidized by color development and a dye forming coupler (referred to hereinafter as a "coupler"). In general, yellow, magenta and cyan colored images which have a complementary color relationship are used to reproduce blue, green and red using the subtractive method of color reproduction. Phenol derivatives or naphthol derivatives are often used as couplers for forming a cyan image. In color photography, the color forming couplers may be added to the developer or they may be incorporated in a photosensitive photographic emulsion layer or another color image forming layer, and a non-diffusible dye is formed by reaction with the oxidized form of a color developing agent which is formed by development.
The reaction between the coupler and the color developing agent occurs at the active site of the coupler. Couplers which have a hydrogen atom at the active site are four equivalent couplers, which is to say, stoichiometrically, they require 4 mol of silver halide with development nuclei in order to form 1 mol of dye. On the other hand, couplers which have a group which can be eliminated as an anion at the active site are two equivalent couplers, which is to say these couplers only require stoichiometrically 2 mol of silver halide which has development nuclei to form 1 mol of dye. Thus, the amount of silver halide in the photosensitive material can generally be reduced and the film thickness can be reduced relative to that when a four equivalent coupler is used, the processing time for the photosensitive material can be shortened and the sharpness of the colored image which is formed is also improved.
Of these cyan couplers, the absorption of the dye which is formed using naphthol type couplers is at a sufficiently long wavelength and there is little overlap with the absorption of the magenta dye image. Moreover since these couplers have a low to a high coupling activity with the oxidized form of a color developing agent they are widely used in photographic applications centered around color negative films. However, the dye images obtained from naphthol type couplers are reduced by ferrous ions which accumulate in fatigued bleach baths and bleach-fix baths and tend to fade (this is known as "reduction fading") and the fastness of the image to heat is poor. As a result, there is a great demand for improvement.
On the other hand, phenol type cyan couplers which have a p-cyanophenylureido group in the 2-position and a carbonamido group which is a ballast group (a group which renders the molecule resistant to diffusion) in the 5-position (referred to hereinafter as ureido cyan couplers) are disclosed in U.S. Pat. No. 4,333,999. The dye formed using these couplers has a deep color shifted by association in the film and they provide colored images which have an excellent hue and provide excellent fastness. As a result, they are now being used widely as couplers to replace the above-described naphthol type cyan couplers.
However, couplers which have a p-cyanophenylureido group in the 2-position and a ballast group in the 5-position generally suffer from the disadvantage that they are readily precipitated. For example, in many cases precipitation occurs during coupler dispersion or when a coupler dispersion is aged in cold storage, and this is a problem in practice. A method in which a specified high boiling point solvent is used in combination is disclosed in JP-A-59-24848, and a method in which amide compounds and non-color forming phenols are used in combination is disclosed in JP-A-61-36746 as ways of overcoming this problem of precipitation. (The term "JP-A" used herein signifies an "unexamined published Japanese patent application".)
However, the performance required of the latest photographic photosensitive materials is even more demanding and the need for higher coupling reactivities and higher dye absorption densities with these couplers continues.
Furthermore, the problem of coupler precipitation described above is clearly a major problem not just during the manufacture of the photographic photosensitive material but also in the manufactured product. More specifically, when a photosensitive material which contains a ureido cyan coupler is stored for a long period under conditions of high temperature and humidity, sometimes the color forming ability falls due to the precipitation of the coupler and this is extremely undesirable in a photosensitive material.